What is the Optimum Temperature with respect to human mortality?

It is well known that the risk of mortality increases at both the high and low ends of the temperature range experienced by a particular population.[1],[2],[3] Therefore, there should be a temperature at which that population’s risk of mortality is at a minimum. [There, however, may be more than one “local” minimum in a graph of mortality risk versus temperature as one proceeds from the lowest to highest temperatures.]

Recently, Guo et al. (2014) undertook a systematic evaluation of the variation in the risk of mortality from non-accidental causes as a function of daily mean temperature in 12 countries. The figures below display their results. They used mortality data for multiple years (ranging from 10 years for Thailand to 38 years for Japan) for 306 communities in the 12 countries, and pooled the data for the communities in each country to derive these figures.

Note that the temperature on the x-axis for each graph is measured in terms of the percentile of the temperature range rather than the actual temperature (in °F or °C). Also, their methodology was designed to account for deaths that occurred over the following 21 days, since additional deaths from exposure to hot or cold temperatures are known to occur for several days subsequent to actual exposure. [The period over which these deaths occur is longer for cold temperatures than for hot.] Their methodology also apparently accounted for “mortality displacement” or “harvesting,” which is the concept that temperature-related deaths that occur in a vulnerable population immediately following the temperature exposure would be partially offset by fewer deaths in that population over the following weeks.[4]

These graphs show that:

· The relative mortality risk for each country is at a minimum between the 66th and 80th percentile of mean temperature. Nine of the twelve countries have an “optimum” temperature between the 72nd and 76th percentiles.

· For each country the relative mortality risk is substantially higher at the 1 percentile temperature (cold end) than at the 99th percentile (hot end).

· Remarkably, the above bullet points hold not only for relatively cold countries such as Canada and South Korea but also the relatively warm ones such as Brazil and Thailand.

The study also reports that, “The minimum-mortality temperatures were higher in countries with high temperature or in countries close to equator.”

What all this means is that, first, because (a) there are more days during the year that are cooler than the optimum, and (b) relative risk is higher at the cold end than the warm end, more deaths should be associated with temperatures that are colder than optimum than those that are warmer. Hence, if global warming merely slides each curve to the right wholesale, total mortality during the year should drop. But, in fact, global warming is supposed to warm winters more than summers — even so-called Skeptical Science acknowledges this! Therefore, we should get a double dividend from global warming in terms of reduced global mortality.

Figure 1: Relative risk of mortality (y-axis) as a function of mean daily temperature plotted as the percentile of the entire temperature data. Data for each country was pooled. Source Guo et al. (2014).

In summary, there is an optimum temperature which minimizes mortality for any given population, and it is toward the warmer end of what that population generally experiences. Specifically, it is at about the 70th–75th of the mean temperature to which that population is exposed. Finally, if there is any doubt about it, there is a good health-based rationale for:

The essay describes such a litany of “we fixed this and adjusted that” changes in the data that I doubt that the results mean anything at all.
Looks like the authors found another way to fold an origami paper.
At the moment, it is not at all clear what it is supposed to look like; except it is not supposed to be a crane, or a swan.
Do people get paid to do this stuff ??

We’re supposed to believe that people can tie someone’s death to global Temperatures when the entire range of the risk involved is from 1.0 to 1.3.
How many death certificates ever state the cause of death was either global warming or global cooling.
Why is it risky to be in the middle where all the countries have a bump upwards.
I think you could get better results just by playing darts. Specially if you do it in a pub over a couple of tankards.
I think there must be a competition going on in academia, to see which school can devise the most idiotic proposition to present for a research grant.
Earth Temperature is generally in the range of -90 deg. C to + 60 deg. C, and there are lots of people living and surviving over a good bit of that range.
A shift of a half a deg. C over a century is not likely to have any measurable effect on global mortality rates.

Accidental reasons like drowning and wrecking one’s car are very much more common when the temperatures are good for convertibles and open-air swimming with a beer bottle at hand.
I mean, yeah, you can be dead as a victim of global warming, but at least you were enjoying it.

So why is there are relative rise in mortality around the 50th percentile?
Most boring weather causes ennui and thus a rise in suicides? That seems unlikely but is the best I can come up with.
It’s particularly noticeable on the UK chart but seems common to many of the countries.

It would be interesting to follow up some of the refs to see if the causes of death , eg cardiac v disease v dehydration etc are available in a similar analysis .
I wonder if the peak at 50th percentile in the UK is associated with the fairly mild , humid, windless and cloudy weather that a friend always calls “bug breeding weather”.

Yes, that makes sense.
The median temperature for the area is the temperature that flora and fauna have evolved to thrive in.
That includes man’s predators, viruses and bacteria.
We face a greater challenge in the middle temperature. And the misty, humid UK is particularly vulnerable to diseases.

Half of the pedestrians killed on the roads in the USA, are killed on pedestrian crossings when they had the right of way.
No it has nothing to do with “that’s where everyone crosses the road.”
It’s because that is the widest part and cars can get you from four directions at once.
If the rule was; “Either cars move, or pedestrians move, but NEVER both at once”, then nobody would be killed on a pedestrian crossing.

The extremes are periods of lower activity. People stay inside or in the shade and minimize activity. The median range however is where activity peaks, so you expect more deaths due to accidents. Whereas the extremes are the weather itself is lethal.

The subsidiary peak occurs for all the countries shown, even Canada [albeit only very slight].
Possibly people feel comfortable at the 50 percentile and engage in more outside activities with an accompanying rise in accidents/deaths……bicycle riding for instance, or playing around with powerboats or water skiing ??
Maybe.

This analysis doesn’t say anything about Global Warming mortality. For that, one would have to test if a population such as UK with its existing temp/mortality curve were to be slowly transferred to an Italy (for example) temp/mortality curve would there be more or less deaths. I.e. is there a systematic difference in the curves in populations in warm versus cold climates. (I’m assuming that it is the climate that is the independent variable not the population).
Especially the way the study is done, with temperature given as a % of temperature data. If the average increases why would one assume that the curve would change shape rather than just slide up a comparable amount.
People are adaptable after all.

This study could be done now, my family emigrated from England to Australia in the 70’s, along with significant numbers of similar families. Someone just has to sought the data and ask the right questions.

Yep, people have mostly adapted to the cold by wearing clothes and better shelters. Humans are basically tropical animals. It is also pointed out that our optimal air temperature on land is 27°C.

A naked person will start to feel cold if the surrounding temperature drops below around 25°C (77°F). Physiological responses such as shivering and diverting blood away from the extremities and surface of the skin will then kick in.

The IPCC acknowledges that ‘warmer’ winters should result in a “decrease cold-related mortality”. I may be mistaken but I vaguely recall that under global warming most of the ‘warming’ will be felt at night, in winter and as you head away from the equator and towards the poles.
You now have to wonder why global warming will kill more people.

Below about 82F (28C), which is the temperature of the tropical jungles, the naked human cannot generate enough energy to overcome radiated heat loss (about 150 watts). We died of exposure.
This suggests that we originally evolved in the jungles, and that the tropical jungles are about the same temperature today as they have been for the past couple of million years.

Perhaps Paraguay people are happier, but my 75% Swedish genes detest dew points over 70°F and aren’t real fond with them over 60°F. Then again, my idea of a good time is hiking in the mountains or a long bicycle ride, not lying on a beach.

Too right – here in tropical Hervey Bay, where the daytime temperature rarely drops below 60F, and is usually a lot higher, the gravest risk to my life is the risk of being run down by a pensioner in a souped up mobility scooter!

In the UK, our bog standard weather tends to occur when the wind is blowing in off the Atlantic. Our extremes of hot and cold are most likely when there is little wind or it’s blowing in off the continent. I suspect that the UK mortality figures are affected by the wind direction in addition to the temps.

AN interesting a viable suggestion. In southern California they get the Santa Anas, which are miserable winds that blow off the deserts, over the San Gabriels and out to sea. Homicide rates are roughly doubled during Santa Anas.

I recall Richard Tol claiming in one blog debate that there is an optimum climate and it is the climate of Florence. At first I thought he was joking. The relativism of this result makes more sense to me, and it is just one more thing making it hard to take seriously the cost/benefit analysis of the economists.

Regardless of country the optimum temperature is around the 75th percentile. what this shows is that human adapt to a wide range of regional temperatures without the slightest regard for global temperatures.

“Results and Conclusions: Three of the studied meteorological factors (daily average temperature, atmospheric pressure and relative humidity) all have relevant and significant influences on ACS incidences for the entire population. However, the ACS incidence for the population over 65 is only affected by daily average temperature, while the ACS incidence for the population under 65 is affected by daily average pressure and humidity. In terms of ambient temperature, the overall findings of our study are in line with the findings of the majority of contemporary European studies, which also note a negative correlation. The results regarding atmospheric pressure and humidity are less in line, due to considerable variations in results. Additionally, the number of available European studies on atmospheric pressure and humidity is relatively low. The fourth studied variable—season—does not influence ACS incidence in a statistically significant way.”http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4245633/

One comment might be that mortality increase occurs when a population encounters UNUSUAL weather. But you need to look at the culture to predict what kind of unusual weather would be worst.
A population is (we assume) adapted to living in a particular temperature range – this adaptation includes physiological features, environmental features such as house type, and behavioral features such as methods of working and relaxation. All these will be optimised for the local weather conditions.
You need to look at these adaptations and predict how well they will stand either higher or lower temperatures. For instance, igloos can probably withstand extreme cold, but may collapse in a hot spell. A culture where the young girls go out night-clubbing with minimal clothing is likely to suffer if the weather gets cold.

A culture where the young girls go out night-clubbing with minimal clothing is likely to suffer if the weather gets cold.
You can easily disprove this theory by going to Newcastle-upon-Tyne, UK (Newcastle NSW may be different).
There, on any winter weekend, you can see girls in minimal clothing and men in T-shits, complaining that the snow is too hot.
The only physiological change I can determine is that the girls legs, if not fake-tanned, are a rather fetching blue colour.

I’m near Newcastle, NSW Australia. and I can tell you that the only reason anyone here takes summer in a colder place is for the skiing.
Long weekend in summer, everyone is heading up the coast, especially from Sydney, roads are jam packed !!
(heading north means warmer down here)
Even in summer, most people from somewhere as nice and warm and ideal as the mid coast of NSW….
STILL seek somewhere warmer. !!

Note that the temperature on the y-axis for each graph is measured in terms of the percentile of the temperature range rather than the actual temperature (in °F or °C).
Should read “x-axis.”
[please verify it is now properly edited. .mod]

It will be difficult days in the north-eastern US. First, freezing rain, frost later come back.http://vortex.accuweather.com/adc2004/pub/includes/columns/newsstory/2015/650x366_03020044_hd30.jpg
“The milder and more spring-like weather headed to the Midwest and Northeast will only be brief. Fresh arctic air will quickly return Wednesday through Thursday.
While slowing down the snow melt and easing the flood threat, the arctic blast will arrive fast for any wet or slushy areas to freeze and turn icy.
The arrival of the colder air will also coincide with when a new batch of rain will spread from the southern Plains to the East Coast. As the cold air slams into the rain, a changeover to treacherous ice or snow will occur in a large swath from Texas and the lower Mississippi Valley to the mid-Atlantic and potentially a part of the Northeast.”

Mortality rate is not expressed as per person, but person and per unit time.
Like, how many people out of 100,000 are expected to die during a year (and in this article, accidental causes were excluded).

icouldnthelpit
?
Not sure how to reply to that. It’s too early here in the UK for drinking. But Cheers to you anyway.
Now, are you implying that you do think that weather is controlled by man?
Or are you saying that you think weather is not controlled by man but climate is?
Either way I think you need to be a little clearer in your communication.

icouldnthelpit
“Can be” and “is” are not the same thing.
Yet again you evade the issue when someone questions what seems to be nonsense from you.
M Courtney asked you to clarify your words when he wrote

Now, are you implying that you do think that weather is controlled by man?
Or are you saying that you think weather is not controlled by man but climate is?

Your reply to that request provides an untrue ad hom. then says

To answer your questions, I think the climate can be influenced by man.

That is NOT what was asked.
Please answer M Courtney’s request for clarification or apologise for trolling the thread.
Richard

icouldnthelpit,
Ah right. So on your scale you are at point 1. It’s Not Happening.
Climate might be influenced by man – just like it might be influenced by a butterfly’s wing…. but we do agree that man does not have a controlling influence on weather or climate.
So certainly not more than 50%.
I’m a little less sceptical than the position you have found yourself in but at least I am clear.

Since humans evolved with very little body hair and fat, it would seem that as a species, we are not naturally adapted to live in any climate where we would not be able to survive year round, outside, wearing only swimming trunks or a bikini.

On evolution of humans some argue that Turkana Basin and the Danakil (Afar) Depression were central to early human evolution. It is pointed out that the Danakil Depression is among the hottest, permanently inhabited places on Earth. Could this be why we are hairless? Maybe an expert here would like to chime in.

Abstract – 2010
Benjamin H. Passeya et alHigh-temperature environments of human evolution in East Africa based on bond ordering in paleosol carbonates
Many important hominid-bearing fossil localities in East Africa are in regions that are extremely hot and dry. Although humans are well adapted to such conditions, it has been inferred that East African environments were cooler or more wooded during the Pliocene and Pleistocene when this region was a central stage of human evolution. Here we show that the Turkana Basin, Kenya—today one of the hottest places on Earth—has been continually hot during the past 4 million years. The distribution of 13C-18O bonds in paleosol carbonates indicates that soil temperatures during periods of carbonate formation were typically above 30 °C and often in excess of 35 °C……http://www.pnas.org/content/107/25/11245.short
======
Letters to Nature – 1998A one-million-year-old Homo cranium from the Danakil (Afar) Depression of Eritrea
One of the most contentious topics in the study of human evolution is that of the time, place and mode of origin of Homo sapiens1, 2, 3. The discovery in the Northern Danakil (Afar) Depression, Eritrea, of a well-preserved Homo cranium with a mixture of characters typical of H. erectus and H. sapiens contributes significantly to this debate……http://dx.doi.org/10.1038%2F30954

Gamecock
March 2, 2015 at 4:36 am
Humans are not hairless, our body hair is just minimal. I have known people with heavy body hair.

I know we have hair but I should have phrased it better. So let me re-phrase.
“Could this be why we have so much less hair than other apes?”
Your hairy friend should go seek a good hair removal cream at his (or her) local pharmacy. 😉

There is no reason to believe we didn’t have heavier hair in prehistoric times.

At some point in time we lost most of our hair for one reason or another. It’s a minor point a per my point and the focus of my reference was on high temperatures and human evolution.
From my top reference in their full paper version I see this:

Implications for Human Thermophysiology.
This temperature record is relevant to the evolutionary origin or maintenance of a unique suite of adaptations that permit humans to remain active under high ambient heat loads. For example, upright posture in hot, open environments confers thermophysiological advantages to bipedal hominins owing to reduced interception of direct solar radiation and to displacement of the body away from the near-surface environment, which may be excessively hot due to solar heating (29). Derived human traits such as very little body hair, high sweating capacity, and high surface area to volume ratio are also advantageous for daytime activity in hot, arid climates (30), and temperature is a central variable in hypotheses of behaviors such as long-distance scavenging and persistence hunting (31). However, the thermoregulatory advantages of these adaptations arise primarily under very hot, sunny conditions (29, 32, 33). Our results suggest that such conditions were relevant to human ecology in the Turkana Basin, either directly within or at the spatial or temporal margins of human-preferred habitats….
—
It is likely that numerous independent factors were involved in the evolutionary origin and maintenance of traits such as bipedal locomotion, slender body form, reduction of functional body hair, and high sweating capacity……http://www.pnas.org/content/107/25/11245.full

Human beings ability to shed heat allows us to continue to expend energy in hot climates where other animals would overheat. Thus, in a hot climate a human can run down faster animals, because we can continue running longer.

There are two correlations that need to be kept in mind when considering these results and what they mean for energy and climate policy.
Correlation 1. Infant mortlity is strongly negatively correlated to Per capita GDP.http://commons.m.wikimedia.org/wiki/File:Infant_deaths_vs_GDP_per_capita_(PPP).png
Correlation 2. Energy useage per capita is positively correlated to per capita GDP.http://notrickszone.com/wp-content/uploads/2012/06/Caryl1.gif
The Congo (tropics) will never have the climate of Lichtenstein, but denying the people of sub-Saharan Africa affordable energy consigns their families to high infant mortality, and that drives much higher population fertility rates (and world population growth). So while the Greenie watermelons of the world believe that to “Save the Planet” we must eliminate inexpensive carbon-forms of energy, the effect of doing so actually may (likely) have the opposite consequence.

Joel, I often explain to Malthusians that if they really want us to slow down population growth then cheap, abundant energy is one of the important keys. The other is economic growth (from that energy). Global fertility was higher back in the 1960s than today, even in Africa. There are many (well off) countries where they are below the replacement level.

Economist – Oct 22nd 2011
Odd though it seems, however, the growth in the world’s population is actually slowing. The peak of population growth was in the late 1960s, when the total was rising by almost 2% a year. Now the rate is half that.http://www.economist.com/node/21533364

In old age Karl Malthus was starting to recognize the creativity of humans, that we conserve and substitute. IOW, he was headed toward reversing his beliefs.
Of course the negative mentality that repeats his fallacious claims doesn’t dig into such.
The book The Doomsday Myth reports on a number of cases where conservation and substitution in response to economic pressure avoided shortages, even in the face of government force.
Rubber is a particularly interesting case of government force:
– Brazil forbid export of rubber plants, to conserve and maximize the price of rubber. Of course that didn’t work, someone got plants to SE Asia where people farmed them, giving much greater supply.
– England and Holland then tried to corner the market, discouraging development of natural rubber for example. But the war restricted supply. Fortunately Americans developed an artificial substitute, helping win the war.

Agreed Keith. And thanks for the book suggestion. I’ll look for it on my Amazon Kindle account.
Regards. J
It is quite sad that the Eco-Greens of our western culture want to deprive the mother’s developing world of the energy they need to raise their families. That is, Energy you and I had and took for granted.

The shape of those lines (flatness versus curviness) has at least a partial explanation in this graph.http://en.m.wikipedia.org/wiki/Energy_intensity#/media/File:Gdp-energy-efficiency.jpg
My interpretation: Canada and the USA get those flatter lines by being less energy efficient (i.e. our big SUVs and trucks are a lot safer than a mini when we get hit by that lorry. And gas powered 10 hp snow blowers saves many heart attacks over the shovel powered snow removal where petrol is 4X higher.).

Is something wrong with the graph? It shows a GDP per capita of less than $15,000 for Saudi Arabia. Wiki gives GDP (PPP) per capita as nearly $54,000. There’s no way Saudi belongs in the same bubble as Russia and the Ukraine

Is something wrong with the graph?
==========
yes, it labels efficient and inefficient incorrectly. Canada at about $80/million btu is much MORE efficient than Bangladesh at $450/million btu.
Countries with a high price of energy are hardly efficient. If they were, they would be able to use their efficiency to get their energy costs down. It is the inefficiency in their economies that keeps prices high.

You confuse “efficient” with better. An advanced country farmer can cultivate and harvest a 100 acre plot by himself using modern machinery — but uses many million BTUs of fossil carbon energy to do so. In Bangladesh, that same level of agricultural production is human or animal powered, using far fewer BTUs of carbon energy. Clearing a driveway of 10 cm of snow with a shovel over hrs of labor is much more carbon energy efficient than using a gas powered snow blower, but there’s no doubt in my opinion which is better. But GreenPeace would rather in throw-out my back shoveling than releasing 2 additional Kg of carbon to the atmosphere with a gas snowblower.

When Greens, enviro-mentals and Obama finally outlaw fossil fuels or force reductions and cause an unstable power grid resulting in massive black-outs at the worst times, take a wild guess which will result in greater mortality- severe freezing or balmy Summer.

Interesting. It is unfortunate that quality of life does not correlate with longevity or mortality. I live at N45 for the agedness of my senior neighbors. Physically difficult lifestyles, lots of fish, low stress, good genes. I think I’ll stay here where the temperature is hovering well below the freezing point of water.

Our high GDP per capita and inexpensive carbon energy enables such lifestyle choices. Imagine your quality of life at half your wealth/income and 4x higher fuel costs. Obama and the Greens want us to experience both, whilst a political elite class of Al Gore, DiCaprio, and Obama retain their lifestyles.

I live at just North of N44, and think it’s great, but would not be nearly so impressed without gas snow blowers, chain saw and a 4WD pickup. In other words, a 19th century lifestyle up here might not make for a long and happy life.

Global warming would be nice to go along with the increasing CO2. Not only would we have fewer people suffering from the cold, but we could have longer growing seasons to utilize the extra CO2. Alas, the possible, tiny amount of warming caused by the extra CO2 is likely to be insignificant in the face of a generally cooling climate.

Here in western MD, the Hagerstown MD observer (I’m 60 miles west of him and a couple degrees colder) had an avg Feb temp of 23.2F — fourth coldest since 1898. That’s a whopping 10.3F below avg for Feb.

Oh, and by the sound of it, it is currently raining (or drizzling) like it has been much through the winter. Now if this is what global climate change does, it is really boring and depressing, but you can’t call the weather hot by any means.

@soarergtl March 2, 2015 at 2:55 am
<i…
“A culture where the young girls go out night-clubbing with minimal clothing is likely to suffer if the weather gets cold.”
You can easily disprove this theory by going to Newcastle-upon-Tyne, UK (Newcastle NSW may be different). There, on any winter weekend, you can see girls in minimal clothing and men in T-shits, complaining that the snow is too hot. The only physiological change I can determine is that the girls legs, if not fake-tanned, are a rather fetching blue colour….
Ah, well – lets look at the mortality statistics.
Cardiovascular disease health profile – Newcastle upon Tyne
Early cardiovascular mortality (<75 yrs)
Newcastle 73.5
England Average 58.8
My hypothesis is proven! (using the approved Climate Change argument that we can't think of anything else it might be…)

@ berniel March 2, 2015 at 2:25 am I recall Richard Tol claiming in one blog debate that there is an optimum climate and it is the climate of Florence….
So… We’re paying all this money to convert the entire world’s climate to that of Florence?
I don’t think we’re spending enough…

Winter
We’ve had a first sprinkle of snow. It came last week. Today was cold and I was lovingly reminded to wear a hat. Winter is waiting. This poem by Julian Tuwim is in anticipation.
Winter
by Julian Tuwim
Six O’Clock dark,
A cold day begins,
The rattle in the park,
Of clattering tins.
Clank on cobblestone,
Slowly and far.
In grey-bluish tins,
Milk gurgles in its jars.
Horses blow mist,
The people shake,
Wagons persist,
Hard-hobbling awake.
Six O’Clock dark,
A cold day begins,
Comes into my dream,
The drum-roll of tins.
In a sheepskin jacket,
I doze on the bench,
Breathing like a mother,
In my frost dream’s clench.
My life in dreams,
Frozen in flight,
Engulfed by spluttering,
Milky and white.
White and warm,
A motherly gurgle,
Comforts me, hides me,
Beneath the burqa of winter.
Now I’ve been begun,
Already I’m starting,
Gasping-meandering,
In this maternal dream.
In a faraway milk,
An echo sways,
The wagon rumbles,
Still quieter, farther away.http://paczemoj.blogspot.com/2010/11/winter.html

A question that should be even more important to those who worship the creation rather than the creator would be “what is the optimum temperature for the present biosphere.” But alas, in their rush to impose new taxes and laws that grow government and reduce personal liberty in order to mitigate climate change, progressives don’t have time for that question. I wonder why?

Probably explained by influenza season in the temperate regions associated with winter and the rainy season associated with the cooler weather in the tropics.
It seems like there should be further study into the correlation for the countries that appear to show a high dependence of morality on temperature, i.e. Italy, Taiwan.

Fair enough that there should be a minimum around 75% of the temperature range – “we like it hot”. But why should there be a half-hearted attempt at a minimum at around 25% of the temperature range? Is this an artifact of the statistical process (like that silly hockey stick – or is there an (unstated) valid reason for this?
For those who mentioned the possibility of hair loss as due to water, suggest you get hold of a copy of “The Descent of Woman” by Elaine Morgan. She wrote a pretty good non-technical introduction to the Aquatic Ape hypothesis. Pooh-poohed by academics as she was a writer, not a university lecturer/researcher; they dismissed her views. Just like crusted-on Professors of Alarmism decry the views of intelligent sceptics. Same old, same old. Oh, dear, when will they ever learn?

I didn’t have time to read through all the “thoughts” above, but seems allowing the average to increase would exchange people saved from the cold with people killed by the heat.
And there seems to be a bias on the graphs, what with them being most from places that have winters, Thailand and Taiwan excepted. What about places like India which has no cold weather but lots of hot.

trafamadore
March 2, 2015 at 9:01 am
……….
And there seems to be a bias on the graphs, what with them being most from places that have winters, Thailand and Taiwan excepted. What about places like India which has no cold weather but lots of hot.

I will assume that you mis-spoke (wrote) there. The Himalayas, with its glaciers, span five countries: India, Nepal, Bhutan, China (Tibet), and Pakistan.

And what % of indians have ever seen snow? Not many. For sure, none of the Indians I know, and that’s a few. But you miss the point of my post (how unusual at whats up): people in warm climates don’t see cold weather. So you make things worse for them, and I think that is the majority of the people in the most populated places on earth.

It’s arguable that the temperature range of the very stable Holocene is “optimal” for human life. It’s not clear that warmer temperatures, like those of say the Eemian would be necessarily better or worse, though the 6-8 m higher sea levels should prompt one to think about coastal infrastructure. One thing which is pretty clear to me: sustained wet bulb temperatures above 35 °C are pretty much 100% fatal, though much depends on amplitude, duration and individual fitness — an hour in the sauna pouring water on the hot rocks won’t get most people, but a week of that would slow cook anyone for sure. That’s resting metabolism. Add hard physical labor to the mix — say working a rice paddy — and the danger threshold gets even lower.
Or another way of putting it, the closer to 35 °C wet bulb temps, the lower the labor output. Plants may very well grow like gangbusters at 560 ppmv CO2, but a lot of staple foods come from parts of the world where few have ever seen a combine harvester in the flesh, much less an air-conditioned one.

The OP asks what the optimal temperature is. Given the inherent uncertainties in projecting the as-yet unexperienced future, setting an upper limit by way of wet-bulb temperature seemed appropriate.
Even the worst-case AR5 projection doesn’t get there by 2200, however it’s not necessary for 100% of the surface to experience those kinds of temperatures to be potentially disruptive: http://www.gfdl.noaa.gov/news-app/story.77http://www.gfdl.noaa.gov/pix/news/labor_capacity-1.gif
Yah, models. Keep in mind they could be wrong on the conservative side. Personally, I’d rather not find out empirically — we know a lot better how crops and field laborers do in the present regime than forward-looking computer simulations are ever going to be able to tell us.

+1°C out right now. The humidity is 99% RH, but absolute humidity is lower.

I’m sure the folks at the Weather Channel would find that quite topical.

Lets return to the case after Great Britain starts producing bananas.

People migrating poleward from the tropics are going to need to live somewhere. Better hope CO2, oh, quadruples those banana yields. And does the same for rice, wheat and corn. And that the models you’re using for those estimates are better than the whiz kids at GFDL have done.

Brandon,
The thing is I really can’t take the models seriously. After tweaking them to not do runaway ice age or boiling, they don’t make me feel they describe the earth. Why could I not be wrong. On the other hand, I’ve not been particularly impressed on successful predictions based on them.
I have today here probably 2-3 C warmer year than when my great-grandfather suffered the extremely cold summers. That is not a bad thing. I have great difficulties seeing any trouble in the next 2-3C, should it come. And that’s mostly the arctic winter. Summers are less affected, partly because clouds will cool a summerday, when during the winter they make it milder.
I know mentioning the days temp is off topic, it is just very difficult to see how on earth you could get this planet so hot throughout these northern latitudes.
Thailand OTOH is very much 35C/100%RH already today.

What I won’t take seriously are arguments along the lines of, “the models suck” followed by “we’ll adapt”. It’s not a logically consistent position.

I know mentioning the days temp is off topic, it is just very difficult to see how on earth you could get this planet so hot throughout these northern latitudes.

Your personal incredulity is something only you can overcome for yourself. I look to data, and they tell me that high northern latitudes are warming faster than the rest of the planet as per predictions from paleoclimate observations.

Thailand OTOH is very much 35C/100%RH already today.

Not according to this paper: http://www.pnas.org/content/107/21/9552.full… the highest instantaneous TW anywhere on Earth today is about 30 °C (with a tiny fraction of values reaching 31 °C). The most-common TW(max ) is 26–27 °C, only a few degrees lower.
And not according to common sense either. Sustained wet bulb temps above 35 °C are simply not survivable without air conditioning. A fan won’t cut it.
What boggles my mind is this: if you actually think Thailand is that close to the survivability limit, why on Earth would you be content to allow things to get even warmer? Do you just not get it that I’m NOT talking about the kind of heat that drinking more water and taking a few salt pills can handle?Humans maintain a core body temperature near 37 °C that varies slightly among individuals but does not adapt to local climate. Human skin temperature is strongly regulated at 35 °C or below under normal conditions, because the skin must be cooler than body core in order for metabolic heat to be conducted to the skin (17). Sustained skin temperatures above 35 °C imply elevated core body temperatures (hyperthermia), which reach lethal values (42–43 °C) for skin temperatures of 37–38 °C even for acclimated and fit individuals (18, 19, 20, 21). We would thus expect sufficiently long periods of TW > 35 °C to be intolerable.
Again, that assumes a resting metabolism. As in NOT doing intensive manual labor outside in sunlight harvesting YOUR food. As in, the WBT does not need to reach 35 °C for it to be an incrementally costly problem.

Dr. Goklany takes an incredibly narrow view of the human condition. Climate change will cause all kinds of disruptions to economies (droughts, extreme winter weather, sea level rise, etc.), with many direct and indirect impacts on health and mortality (or premature mortality, for all those who point out mortality is 100%), but apparently he is not capable of any kind of systems thinking. Also, there are many people on the planet who don’t have the luxury or vacationing or retiring to warmer climes. This is an example of a 1%-er using about 1% of his brain. Just pure stupidity.

Climate change will cause all kinds of disruptions to economies
====================
so lets stop using fossil fuels because that for sure wont disrupt economies. all that extra cash we will all have in our pockets, not having to spend it on oil and gas. instead we can burn it to stay warm.

Ask any older person (such as myself) you’ll find that their tolerance for lower temperatures is less the older they get. (Florida isn’t a retirement target just because of taxes).
I need a higher temperature when just sitting around. Feel more easily chilled with lower temps.
I keep asking “Where’s all this Global Warming I’ve been promised”?
Can I sue Al for breech of contract or false advertising maybe?

“Hence, if global warming merely slides each curve to the right wholesale, total mortality during the year should drop” does not follow from ” “The minimum-mortality temperatures were higher in countries with high temperature or in countries close to equator.” What would happen, would be that the characteristics of the mortality-temperature curve would change.

If we want to move beyond constantly reacting to BS spewed by AGW fanatics, we need to seize control of the conversation. There are real threats related to the climate. Namely, mega-droughts and the eventual end of the interglacial. Even barring the end of the interglacial, another 1814 would be no picnic. Discuss these issues, discuss plans to mitigate their impacts, force the media and public officials to confront them.

I’m suspicious.
Note that only three countries have a great increase with high temperature, and they aren’t especially hot countries nor especially poor ones where other factors could be in play. (Italy, Spain, and Taiwan.)

… is there a systematic difference in the curves in populations in warm versus cold climates.
… If the average increases why would one assume that the curve would change shape rather than just slide up a comparable amount.

RESPONSE:
1. According to the Guo paper, “minimum mortality” tends to occur at higher temperatures in warmer areas.
2. I am not assuming that the curve would change shape, although I would expect it would because of acclimation and adaptation.Jimbo March 2, 2015 at 5:48 am

I often explain to Malthusians that if they really want us to slow down population growth then cheap, abundant energy is one of the important keys. The other is economic growth (from that energy). Global fertility was higher back in the 1960s than today, even in Africa.

Fair enough that there should be a minimum around 75% of the temperature range – “we like it hot”. But why should there be a half-hearted attempt at a minimum at around 25% of the temperature range? Is this an artifact of the statistical process (like that silly hockey stick – or is there an (unstated) valid reason for this?

RESPONSE: There does seem to be a local minimum at ~ 25% for some countries, but I think it is more useful to think of this as a minor max at ~50%. This might be because temperature by itself is too one dimensional a measure. Humidity could be important too, and changes in humidity may be responsible for this minor max. famadore March 2, 2015 at 9:01 am

… seems allowing the average to increase would exchange people saved from the cold with people killed by the heat.
And there seems to be a bias on the graphs, what with them being most from places that have winters, Thailand and Taiwan excepted. What about places like India which has no cold weather but lots of hot.

RESPONSE:
1. Not quite since there is a increase in risk is higher at the cold end than the warm end.
2. (a) Don’t forget Brazil, and Australia and China have many areas that are quite warm. (b) Part of the problem is data availability. Many of the warm weather countries are also poorer and less well-developed, and probably don’t keep statistics as meticulously as the richer countries.

Dr. Goklany takes an incredibly narrow view of the human condition. Climate change will cause all kinds of disruptions to economies (droughts, extreme winter weather, sea level rise, etc.), with many direct and indirect impacts on health and mortality (or premature mortality, for all those who point out mortality is 100%), but apparently he is not capable of any kind of systems thinking. Also, there are many people on the planet who don’t have the luxury or vacationing or retiring to warmer climes. This is an example of a 1%-er using about 1% of his brain. Just pure stupidity.

“Hence, if global warming merely slides each curve to the right wholesale, total mortality during the year should drop” does not follow from ” “The minimum-mortality temperatures were higher in countries with high temperature or in countries close to equator.” What would happen, would be that the characteristics of the mortality-temperature curve would change.

RESPONSE: I agree that the former doesn’t follow from the latter. The “if” is just there to signal that an assumption is about to be made. Perhaps I should have said, “If ONE ASSUMES THAT global warming…” Nor do I believe that this is likely. In fact, I agree that the mortality-temperature curve would change because of acclimation and adaptation. The curve would, moreover, be different for different populations because social, economic and other factors (e.g., wealth, nutrition and availability of food, etc.) vary from population to population.

For this there had to be a study?
Who paid for it, and why?
The comfortable (healthy and happy) temperature is whatever a person would set his home thermostat on if the heat was free — lets say 70 degrees F.in the winter and 75 degrees F. in the summer based on my own preferences. Now let’s move on to study something important. .
How would you adjust the temperature numbers for effects of humidity and wind speed — both are obviously important factors in addition to temperature.
Any doctor would have told you heart attacks are much more common in the winter.
Consider a man over 50 years old who has to drive to a job he doesn’t like on Monday morning but he is running late and his car is stuck in a pile of snow in his driveway — he’d be better off calling in sick and going back to bed, because everyone “knows” that’s heart attack time.
I have read that a nude person outdoors can not survive a full day without clothing and a fire if the temperature is below 70 degrees F. and there is at least a small wind — although I have not tried it — don’t want to scare the neighbors — we are a tropical species that tolerates hot weather much better than cold weather,

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